Method of deadening mercury in blue neon tubes



Patented @ct. 1931 LEO L. BECK, F JACKSON HEIGHTS, NEW YORK, ASSIGNOR T0 CLA'UDE NEON LIGHTS, I

mo, 0? NEW YOB N. 3., A COMORATIOH OF NEW YORK THOD 0F D Ito Drawing.

. lamps.

en such a lighting system is used commercially, as for advertisin sign lighting,

the tubes or portions thereo are frequently disposed in a substantially vertical position,-

in which event, during periods of inactivity, the mercury vapor tends to condense and collect in the lowermost portions of the tubes and in all circumstances, it hasbeen found uite dificult to maintain an. even distribution of the mercury throughout the tube.

The present invention has forsits object to efiect an even' distribution of the mercury throughout the tube under all conditions, that is, to deaden the motion of the mercury in the tube so that it may not tend to collect in certain areas and leave portions'of the tube free of mercury. To this end the mercury is caused to collect in small globules on the walls of the tube throughout its entire length durbeen discovered that an amalgamation of the mercury with a small percentage of one of the elements of the alkali metals group, lithium, sodium, potassium, rubidium, or caesium, will cause the mercury to adhere readily on condensation to the walls of the tube in the form 0:? small globules.

In order that the invention may be clearly understood and readily carried into effect, one method of pre aring an amalgam suitable "for use in rare ed gas tubes willnow be described using potassium as an example, it being understood that the temperatures and proportions, as well as the steps outlined, are

given by way of example only and may be varied according to circumstances.

The amalgam may be prepared by heatin pure mercury to from about 67 C. to 7 3 and immersing beneath the surface of the:

ing periods of inactivity of the tube. It has 1 3 r MERCURY IN BLUE NEON TUBE8 Application filed February 10, 1927. Serial Bio. 16?,374.

heated mercury, with the aid of a'pair of tweezers, small pieces of clean and pure potassium metal. The potassium melts rap- 1dly and forms a potassium mercury amal m. The two metals are stirred to difi'use thoroughly and the oxide or scum is sed ofi. Preferably the amalgam should contain not more than 1 of potassium.

The amalgam should be kept free from moisture. Best results are obtained when so freshly prepared amalgam is used in the tubes.

When the mercury is thus amalgamated w1th one of the elements of the alkali metals group, its tendency is to collect-during perie5 ods of tube inactivity, in small globules over the walls, which readily vaporize upon the, passage of current through the tube and thus insure the presence of the metallic vapor evenly distributed throughout the tube.

Various modifications may be made in the proportions and temperatures entering into the'preparation' of the amalgam, as well as v in the composition thereof, dependent to some extent upon the particular conditions under which the tube operates, without departing from the spirit and scope of the invention.

What I claim is 2-- 1. A glow discharge luminescent tube containing an amalgam of mercury and an alkali metal, said tube, when on open circuit, having the mercury distributed over the interior surface thereof in the form of small globules, whereby the mercury is readily vaporized upon the passage of'current.

2. A glow discharge luminescent tube containing an amalgam of mercury and potassium, said tube, when on open circuit, having t-he mercury distributed over the interior surface thereof in the form of small globules, whereby the mercury is readily vaporized upon the passage of current. Y

lid

3. A glow discharge luminescent tube cong mercury is readily vaporized upon the passage of current.

d. A glow discharge luminescent tube containing an amalgam of mercury with not more than 1 of potassium, said tube,

. when on open circuit, having the mercury dis tributed over the interior surface thereof in the form of small globules, whereby the mercury is readily vaporized upon the passage of current. i l

5. The method of processing and operating'a glow discharge luminescent tube which comprlses chargin the tube with a rare gas and with an ama gem of mercury with an alkali metal and discharging currents of the order of 15 to 30 milliamperes through the tube at high Voltages whereby the mercury is deposited and distributed upon the interior surface of the tube as fine globules and whereby development of the blue color of the tube upon starting is facilitated.

In testimony whereof I afix my signature.

* LEO L. BECK. 

